The present invention pertains to an unvented gas log set for an unvented fireplace.
On occasions when the appearance of a wood-burning fireplace is desired in a room or structure lacking a flue pipe or it is not desired to withdraw heat and moisture from the room, unvented type fireplaces may be utilized. These unvented types of fireplaces are known to utilize unvented gas log sets which are constrained to exhaust directly into the rooms in which they are installed. In order to comply with strict emission standards promulgated to protect room occupants from potential health risks associated with products of combustion resulting from incomplete or improper combustion, these gas log sets are carefully designed to be clean burning.
Multiple pressure regulators have heretofore been utilized in unvented gas log sets to achieve satisfactory operation. Unlike conventional vented gas log sets in which the fuel pressure provided to the pilot is of little concern and can be regulated by merely, for example, use of a thumb screw, it has been found that the pilot pressure in unvented gas log sets must be carefully regulated. Therefore, in order to regulate the pilot pressure to a pressure which according to conventional design is different than the pressure used for the main burner, a pressure regulator in addition to the regulator used to regulate the pressure to the main burner has typically been added. Although functional, the use of two regulators to separately regulate the fuel pressures of the pilot and the burner may unacceptably increase the cost of the unit.
In addition, because with an unvented gas log set it is important that the flames from the burner not impinge upon the simulated wood logs during operation to prevent potentially dangerous carbon monoxide from being created, both the burner and the logs are conventionally fixedly positioned relative to the set frame. More particularly, normally the burner tube is attached to the frame by spot welding. Besides being relatively expensive, this type of attachment may also make the welded location of the burner susceptible to an undesirable leak or corrosion.
Thus, it is desirable to provide an unvented gas log set which may overcome these shortcomings.